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Propagation and mechanism of decadal upper‐ocean variability in the North Pacific
Author(s) -
Liu Zhengyu,
Zhang RongHua
Publication year - 1999
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/1999gl900081
Subject(s) - thermocline , ocean gyre , geology , climatology , anomaly (physics) , advection , oceanography , forcing (mathematics) , subduction , wind stress , pacific decadal oscillation , sea surface height , sea surface temperature , subtropics , seismology , physics , tectonics , condensed matter physics , fishery , biology , thermodynamics
Two types of anomaly pathways associated with decadal thermocline variability in the North Pacific Ocean are identified on constant density surfaces (isopycnals): one westward and the other southwestward around the subtropical gyre. A theory, based on two buroclinic planetary wave modes in the thermocline, is proposed to account for the observed variability pattern. The variability along the westward wave path is ascribed to the non‐Doppler‐shift 1st mode and seems to be forced mainly by wind stress forcing; the anomaly along the southwestward subduction path is associated with the advective nature of the 2nd mode and could be excited mainly by surface buoyancy anomalies. This study may provide a dynamically unified, three‐dimensional picture of decadal thermocline variability in the North Pacific Ocean.